Brewing Water Chemistry

There is 4 main constituents to beer (hops, yeast, malt, and water) and water is the most abundant of the four constituents.

As water from different regions of the world had different elemental compositions, there were different levels of inorganic minerals dissolved in the water. These minerals had an overall effect on the style of beer in these regions.

Sources of Water:
Ground - rain percolating into the ground.
Surface - River, Lake, Sea-water
Waste Water - discarded water from households which is treated and available as water again.

It is extremely important to know what water sources are being used in the creation of your beer. This not only included the water in the beer but the water used for cleaning, or cooling water. Typically, one gallon of beer made consumes six gallons of water.

From a high level there are three main items that define water. These are the amount of suspended particles, the amount of dissolved components, and the number of microorganisms present. Often drinking water will be required to meet local specifications for microbiological levels, chemical levels, and a host of others. It is important to check with your local specifications.

As water is a solvent, it has the ability to dissolve ions and other molecules into solution. One of the most important dissolved ions relative to brewing is calcium (Ca ++). The tables listed below show all of the critical dissolved minerals and important aspects of each with recommendations for the content present in the water for brewing.

Calcium

Protects enzymes from thermal degradation and extends the enzymatic activity in the warm temperatures during mashing.

Improves trub formations during wort boiling.

Decreases pH during mashing and wort boiling as it precipitates out of solution. This is desirable since the pH of malt and water is above the desired range of 5.2 to 5.6 during mashing.

Recommendation: 80 - 120 ppm calcium in mash tun.

Magnesium

Provides a slightly bitter or sour taste to beer.

Important cofactor in several enzymatic reactions during fermentation.

Magnesium salt such as Epsom can produce a pronounced bitterness.

Rarely is it necessary to add magnesium to brewing water.

Recommendation: 10 - 15 mg/l

Sodium

At lower concentrations, sodium adds a slightly sweet flavor to beer.

At higher concentration (>100 ppm), sodium gives beer a salty flavor.

Brewers often add table salt (NaCl) to the kettle but ceased that practive many decades ago in view of health concerns regarding sodium and high blood pressure.

Recommendation: 0 - 75 ppm

Carbonates (CO3 - Carbonate, HCO3 - Bicarbonate)

Will prevent the decrease of pH in the wort because of the liveration of hydroxy ions (OH).

Twice as effective in raising the wort pH as calcium in in lowering the pH.

Sulphate imparts drier, more bitter flavors in beer. Sulphate also acts as a source of SO2 and H2S, formed during fermentation giving beer a sulfury note (rotten eggs, burnt matches)

Cl Recommendation: 0-40 ppmSO4 Recommendation: 0 - 600 ppm

Chloride (Cl) and Sulphate (SO4)

Chlroide increases palate fullness of the beer.

Chloride gives a mellow flavor to the beer.

Sulphate imparts drier, more bitter flavors in beer. Sulphate also acts as a source of SO2 and H2S, formed during fermentation giving beer a sulfury note (rotten eggs, burnt matches)

Cl Recommendation: 0-40 ppmSO4 Recommendation: 0 - 600 ppm

The other important aspec of water is the hardness. Hardness is defined by the concentration of calcium and magnesium salts dissolved in the water. These can be split into two groups: temporary hardness and permanent hardness. Temporary hardness is made of calcium and magnesium bicarbonates. It is reduced by boiling as CO2 is driven off. Permanent hardness is made up of calcium and magnesium sulphates, chlorides, and nitrates. This is only reduced by ion exchange.

As a home brewer, water softeners work by trading out the calcium and magnesium with sodium ions. Often this effect is increased sodium ions above. Be sure you understand the impact of the contribution of sodium ions present in your water as you likely have traded one problem for another. Reverse osmosis filtration is an excellent way to remove hardness.

Common Brewing Waters:

Analysis

Town

Burton

Munich

Pilsen

Hardness (ppm CaCo3)

906

258

28

Alkalinity (ppm CaCO3)

236

253

23

Calcium 2+

263

76

7

Magnesium 2+

62

18

3

Sulphate SO4 2-

638

10

5

Chloride 1-

36

2

5

Often brewing salts can be added to dial in a specific beer style but my recommendation is to find what works and verify your water is not causing you problems. Often I do not recommend adding brewing salts and instead focus on where probem areas may exist and correct those first. Often more problems can result from brewing salt additions than really benefit the overall beer. However, there are some cases were brewing salts are the only solution.